Glass masking method using lasers

ABSTRACT

Methods and apparatus for masking glazing panels while leaving a peripheral region free of masking material. The method can include providing a masking material and applying the masking material to at least one major surface of the glazing panel. The glazing panel can be either a single glass pane or a multi-pane insulating glass unit. After application to at least one major surface, a laser can be used to describe a closed path on the major surface, thereby cutting or scoring the masking material through to the glass major surface. The path demarcates a central, masked region from a peripheral masked region of the glazing panel. In one method, the laser cuts a muntin bar pattern having several central regions. The laser power can be selected and/or adjusted such that the masking material is burned through, without damage to the underlying glass material and any coatings on the glass material. After cutting through the masking material to define the peripheral masked region, the peripheral masked region can be peeled or stripped off from the masked glazing panel. The remaining panel thus has a protective mask about the central region while leaving the peripheral region unprotected. The resultant masked glazing panel may be assembled into a window unit by mounting window frame members about the four sides of the glazing panel. The window frame members may thus have a tight and durable fit directly to the glass in the peripheral region, while the central region of the glazing panel remains protected by the masking material.

BACKGROUND OF INVENTION

1. Field of the Invention

The present invention relates generally to glass windows and doors. Morespecifically, the present invention relates to preparing glass panelsfor insertion into window frames. The present invention includes methodsfor protecting or masking glass panes to be disposed within windowframes, while leaving the peripheral region free to be better sealedwithin a frame.

2. Description of Related Art

Glazing panels are often mounted within frames such as window frames.The glazing panels can be single glass panes or multi-pane, insulatingglass units. The window panes typically have first and second majorsurfaces with peripheral edges about the major surfaces, and peripheralregions within the peripheral edges. The peripheral regions bound acentral region on each of the first and second major surfaces. The glasspanes are typically ultimately disposed within frames, where the framesare dimensional and configured to accept only the peripheral regions ofthe glass panes, leaving the central regions of the window panesunoccluded. In some uses, the window panes are first formed intoinsulating glass units, having two or more substantially parallel windowpanes separated by spacers there between. In some insulating glassunits, the parallel glass panes are sealed to the spacing member, andthe air between the panes replaced with an inert gas. The resultinginsulating glass unit can then be disposed within a window frame.

Old style windows were often made using several smaller panes of glassheld within smaller frames, which were joined together into one windowunit. Each portion of a double hung window might be formed of 4, 6 or 8window panes held in place within a corresponding number of windowframes. The additional frame members typically required additionalglazing to secure the multiple window panes to the frame. The additionalglazing represented additional labor and additional opportunities forair infiltration. Modern windows are typically formed of larger singlepanels, which are often insulating glass units. Some purchasers desirethe older style appearance, but without the drawbacks. To achieve thesegoals, modern windows can have muntin bars placed over the single glasspanels, to achieve the older style appearance of multiple panes, butwithout the disadvantages. The muntin bars thus represent another set offraming members to be disposed over the glass surface.

It is common for the glass panes and insulating glass units to be formedat one location, protected in some fashion, and shipped to anotherlocation. It is not until arrival at the second location that the glasspanes or insulating glass units are mounted within window frames. Muntinbars may also be mounted at the second location The window frames areoften then shipped to a third location, where they may be installedwithin homes, buildings, or automobiles.

There is an opportunity for damage to the glass panes at many points inthe process, including the transport to the second location prior toframing, and subsequent to framing, prior to arrival at the buildingsite. The glass major surfaces may also be damaged after installation inthe building, for example, during building construction.

For the above-stated reasons, the glass pane major surfaces are oftenmasked, for example, with a polymeric protective film. The protectivefilm can provide some protection from abrasion and scratches to thesurface during the transport or the building construction.

Sheets of masking material may be adhered to one or more of the glasspane surfaces to protect the surfaces from the scratching previouslymentioned. Often, the entire glass pane is masked on at least one majorsurface. The masking material may be cut to the same size as a glasspane major surface. The glass pane may then be inserted within a windowframe adapted in dimension to accept the peripheral region of the glasspane within the window frame. This can be done while the maskingmaterial is in place, leaving the glass major surface protected. Thismethod, however, can leave polymeric material trapped along theperipheral region of the glass pane, between the glass surface and theenclosing frame member. The visible polymeric remnants may be unsightly,and may eventually degrade and/or be pulled out, reducing the integrityof the seal between the glass surface and the enclosing window frame.This can leave a gap between the glass surface and the window frame.

Cutting knives have been used to mechanically cut through the polymericmasking material while the masking material is on the glass surface. Theperipheral strip of masking material thus delineated from the centralregion masking material may be peeled off, leaving the protected centralregion intact. The knife blade used to cut through the polymericmaterial may require an undue amount of adjustment, and may not provideexactly the needed pressure to cut through the polymeric film but notinto the window pane. As windows are increasingly covered with coatings,the knife edge cutting through the outermost window coating can be veryundesirable. What would be desirable are methods for removing themasking material that do not requiring touching the glass pane adheredto the masking material.

SUMMARY OF INVENTION

The present invention provides methods and apparatus for masking glazingpanels with a protective layer, while leaving a peripheral region nearthe glazing panel edges free of masking material to allow betterinsertion and fit into a window frame. In one method, a masking materialis applied over a first major surface of a glazing panel, followed byburning through the masking material along a cutting path which canfollow inside of the edges of the glazing panel, demarcating aperipheral strip of masking material. In one method, a closed pathwithin the periphery of the glazing panel is traveled by the laser beam,thereby forming a scored path through the masking material. Theperipheral strip of masking material thus formed can be removed orpeeled off by a stripper or finger mechanism. The final glazing panelthus has a central region covered with masking material and a peripheralregion free of masking material, ready to be closely fit within a windowframe.

In one method, the masking material is sized such that a top and bottomperipheral region is free of masking material prior to cutting by thelaser beam. This method requires fewer cuts through the maskingmaterial. In another method, the masking material is applied, then amuntin bar pattern is burned through the masking material. The maskingmaterial regions which are to lie under the muntin bars can be removed,and the frame and muntin bars mounted over the partially masked glasspanel.

In still another method, a polymeric masking film is corona treated onone side and coated with an acrylic adhesive on the other side. Thecorona treated side is resistant to adhering to the adhesive, with thecorona treatment obviating the need for a separate release liner. Theadhesive coated masking material may be rolled up and the resultingsupply roll provided to the masking line. In some methods, the adhesiveforce may be primarily a static electrical force.

In the glazing masking line, the masking material may be pulled from thesupply rolls, and pressed against the glazing panels with applicator orpincher rolls. After application to the glass surface, a path within theperiphery of the glazing panel may be described by the laser beam. Inone method, a laser unit is mounted on a carriage mechanism which cantravel with two degrees of freedom, to describe the desired path aboutthe glass masked surface. In one exemplary method, the carriagemechanism has a vertical carriage mechanism mounted on a horizontalcarriage mechanism. The path programmed for the carriage mechanism canvary from run to run. In another method, the laser unit remainsstationary, while the laser beam is made to travel about the desiredpath using a movable mirror.

After a line has been scored or burned through the masking materialabout the periphery, the peripheral strips of masking material thusformed can be grasped by stripping or gripping fingers which can pullthe peripheral strips of masking material from the glazing unit.

The present invention thus provides a rapid method for scoring themasking material, allowing precise definition of the peripheral stripsize desired. The laser beam enables forming score lines through themasking material without burning the underlying glass and underlyingglass coatings. The laser device, which does not physically contact theglass or masking material, is not subject to mechanical wear and willnot damage the glass surface. The frequency and power of the laser beamcan be selected to adequately burn through the masking material but notthe underlying glass.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a highly diagrammatic, side view of a glazing panel to bemasked where the glazing panel can be a glass pane or multi-paneinsulating glass unit;

FIG. 2 is a highly diagrammatic, top view of the glazing panel of FIG.1, prior to masking;

FIG. 3 is a highly diagrammatic, side view of the glazing panel of FIG.1, after masking;

FIG. 4 is a highly diagrammatic, side view of the masked glazing panelof FIG. 3, after scoring by a laser beam about the periphery;

FIG. 4A is a highly diagrammatic, side view of the masked glazing panelof FIG. 3, after scoring by a laser beam in a muntin bar pattern;

FIG. 5 is a highly diagrammatic, side view of the scored, masked,glazing panel of FIG. 4, after the peripheral masking has been peeledoff;

FIG. 5A is a highly diagrammatic, side view of the scored, masked,glazing panel of FIG. 4A, after the peripheral and muntin bar maskinghas been peeled off;

FIG. 6 is a highly diagrammatic, side view of an alternate method ofmasking the glazing panel of FIG. 1, leaving the top and bottomperipheral regions initially free of masking material;

FIG. 7 is a highly diagrammatic, side view of the masked glazing panelof FIG. 6, after lateral scoring by a laser beam;

FIG. 8 is a highly diagrammatic, side view of the masked, scored,glazing panel of FIG. 7, after the lateral peripheral masking stripshave been peeled off;

FIG. 9 is a highly diagrammatic, side view, of the masked and peeledglazing panels of FIGS. 5 or 8, after being disposed within a windowframe;

FIG. 10 is a highly diagrammatic, top, cross-sectional view of thewindow pane and frame of FIG. 9, illustrating the central masked portionof the finished glass unit;

FIG. 11A is a highly diagrammatic, top view of a single sided maskingline including a supply roll, applicator roll, carriage mounted lasercutting beam free to move in two degrees of freedom, and a gripping orpeeling mechanism;

FIG. 11B is a highly diagrammatic, top view of a two sided masking lineincluding supply rolls, applicator rolls, carriage mounted laser cuttingbeam free to move in two degrees of freedom, and a gripping or peelingmechanism; and

FIG. 12 is a highly diagrammatic, side view of the masking applicationline of FIG. 11A.

DETAILED DESCRIPTION

The following detailed description should be read with reference to thedrawings, in which like elements in different drawings are numberedidentically. The drawings, which are not necessarily to scale, depictselected embodiments and are not intended to limit the scope of theinvention. Several forms of invention have been shown and described, andother forms will now be apparent to those skilled in art. It will beunderstood that embodiments shown in drawings and described above aremerely for illustrative purposes, and are not intended to limit scope ofthe invention as defined in the claims which follow.

Referring now to FIG. 1, a glazing panel 20 is illustrated. Glazingpanel 20 can be a single glass pane or an insulating glass unitincluding multiple glass panes separated by spacers. Glazing panel 20includes generally a top edge 22, a bottom edge 24, a right side edge26, and a left side edge 28. Glazing panel 20 includes generally acentral region 34 surrounded by a peripheral or marginal region whichincludes a pair of longitudinal peripheral strips 32 and a pair ofvertical or lateral peripheral strips 30. While the central andperipheral regions are described separately for purposes of illustratingthe invention, the glazing panel typically is the same across thecentral and peripheral regions. Referring now to FIG. 2, glazing panel20 is further illustrated from the top, having a first major surface 40and a second major surface 42 substantially parallel to first majorsurface 40.

Referring now to FIG. 3, glazing panel 20 is illustrated afterapplication of a masking material 44 over at least one of the majorsurfaces 40 and 42. In one method, only first major surface 40 iscovered. In another embodiment, both the first and second major surfacesare covered with masking material 44.

Referring now to FIG. 4, glazing panel 20 is illustrated after the lasercutting of a closed path of score lines through the masking material,but not through the underlying glass pane. Central region 34 may be seento be surrounded by a pair of vertical or lateral score lines 48 and apair of longitudinal score lines 50. In a preferred embodiment, thescore lines are burned entirely through the masking material in a closedpath, leaving no masking material continuity between central region 34and the surrounding peripheral regions. Referring now to FIG. 5, glazingpanel 20 is illustrated after masking material 44 has been removed fromperipheral regions 30 and 32, leaving masking material in central region34.

Referring now to FIGS. 4A and 5A, another embodiment of the invention isillustrated, which can be used with muntin bars. FIG. 4A illustrates amethod similar to the method of FIG. 4, sharing reference numerals forsimilar items. In FIG. 4A, masking material 34 is illustrated afterhaving several closed paths 48A burned through the masking material, aswell as a peripheral closed path 48. In some embodiments, a separateperipheral closed path 48 does not exist, and only the numerous separateclosed paths 48A are formed, which can result in a single contiguouspiece of masking material requiring removal. In such an embodiment, linesegments 47 are not burned through the masking material. Paths 48A maybe seen to form numerous closed paths, defining corresponding centralregions 34A within, and corresponding removable strips 30A without.

FIG. 5A illustrates the masked and scored glass panel of FIG. 4A, aftersome of masking material 44 has been removed. Central masked regions 44Amay be seen to remain on the glass panel, while the masking over theremovable strip areas 30A has been stripped off. At some point in themanufacture, muntin bars can be disposed over the strip portions 30Ahaving no masking material. The masking material within each of themuntin bar faux window panes may be removed at a later time, typicallyafter installation in a building.

Referring now to FIG. 6, an alternate method is illustrated for applyingmasking material 44 to glazing panel 20. In this method, maskingmaterial 44 is sized so as to leave the glass top and bottomlongitudinal peripheral strips 32 free of masking material 44. Maskingmaterial 44 may be seen to cover the central region and the lateralregions on either end. Applying masking material 44 sized in this mannerreduces the cutting requirement. In some methods, the top and bottomlongitudinal strips 32 are already free of masking material to asufficient degree and do not need to be further scored or cut by thelaser beam. Referring now to FIG. 7, glazing panel 20 is illustratedafter lateral score lines 48 have been burned through masking material44 by the laser beam.

Referring now to FIG. 8, glazing panel 20 is illustrated afterperipheral lateral masking material strips have been removed, leavingperipheral regions 30 and 32 free of masking material but leavingmasking material 44 in central region 34. It may be seen that the resultof utilizing the method illustrated in FIG. 6 can form a similar endresult to that of FIG. 5.

Referring now to FIG. 9, further processing of the masked and strippedglazing panels of FIGS. 5 or 8 is illustrated. Glazing panel 20 has beendisposed within a frame 54 about the peripheral region, leaving thecentral region 34 unoccluded. In embodiments having muntin bars, themuntin bars can be attached at this time, within frame 54.

FIG. 10 illustrates framed glazing panel 20 from the top, showing thatcentral region 34 is masked by masking material 44, while the peripheralregion within frame 54 is free of the masking material, thereby allowinga tighter and/or more durable fit between glazing panel 20 and frame 54.

Referring now to FIG. 11A, a single sided glazing masking line 100 isillustrated from the top. Glazing masking line 100 includes severalglazing panels 20 being processed through the line. Glazing panels 20may be seen to be carried through the line by number of conveyor rolls1105. Glass panels 20 can pass generally through a first station 120, asecond station 122, and a third station 124. First station 120 can beused to apply or adhere the masking material 44 to the glass panes 20.Second station 122 may be used to form the score lines about theperiphery of the glass panes. Third station 124 may be used to strip orpeel off the masked peripheral regions. In first station 120, a pair ofmasking material supply rolls 102 may be seen disposed on either side ofglazing panels 20, being applied to glazing panel 20 by applicator orpinch rollers 104.

Second station 122 can include a carriage mechanism 110, which caninclude a horizontal carriage 112 and a vertical carriage 114, which canbe slidably carried on horizontal carriage 112. A laser unit 116 can becarried on vertical carriage 114 and may be seen to be emitting a laserbeam 118 which impinges upon masking material 44 applied to glass pane20. In some embodiments, the horizontal and vertical carriages carry thelaser 116 through a path sufficient to describe a closed, path withinthe edges of a glass pane, to allow later removal of the peripheralmasking material. In other embodiments, a fixed laser is used, togetherwith a mirror for sweeping the laser beam in a path about the peripheryof the glass unit.

Third station 124 may be seen to include a stripper or peeler mechanism130. In one embodiment, stripper mechanism 130 includes numerous peeleror stripper fingers 132 which are biased against glass panel 20 in orderto grasp and peel off masking material 44 in the peripheral regions. Insome embodiments, stripper fingers 132 extend along the vertical edge ofglazing panel in order to grasp the leading edge of the lateral orvertical peripheral strip to be removed as well as the lateral top andbottom strips to be removed. The finished, masked and stripped glazingpanels may be seen as indicated at 140 in FIG. 11A.

Referring now to FIG. 11B, a double sided glazing masking line 101 isillustrated from the top. Double sided line 101 can be similar to line100 of FIG. 11A. Double sided line 101 has a second supply roll 102A, asecond applicator roll 104A, a second side carriage mechanism 11A havinga horizontal carriage 112A, a vertical carriage 114A, and a laser 116A.A second side stripper mechanism 130A having numerous stripper fingers132A may also be seen. Double sided line 101 may be used when masking ofboth sides of a glass panel is desired.

Referring now to FIG. 12, the glazing masking line 100 of FIG. 11A isillustrated from the side. A carriage mechanism 110 may be seen toinclude the horizontal carriage component 112 and the vertical carriagecomponent 114 for carrying laser 116 thereon. Stripper mechanism 130 maybe seen to include numerous stripper fingers 132.

In a preferred embodiment of the present invention, the path describedby the laser cutting demarcates a central, masked region from aperipheral strip region which is to be removed. In one preferredembodiment of the invention, this path demarcates the central, maskedregion such that when the frame members and/or muntin bars are put inplace over the glazing panel, the frame members and muntin bars do notoverlie the central, masked region or regions. In this preferredembodiment, all peripheral edges of the central region may be disposedslightly inside of the surrounding frame members and/or muntin bars.This allows all edges of the central region to be grasped and peeledoff, manually if need be. This also can provide a tight seal between theframe members and/or muntin bars, and the unmasked glazing paneldirectly underneath.

In another embodiment of the present invention, the path described bythe laser cutting follows a path slightly inside of the region to beoverlaid by the frame members and/or muntin bars. This path would thusbe slightly outside of, and larger than, the path designed to have thecentral, masked region totally within the frame members and/or muntinbars. The central, masked region would thus be slightly overlaid by theframe members and/or muntin bars on one, some, or all peripheral edgesof the central, masked region.

In one embodiment, the central, masked region is laser cut so as to haveonly one edge slightly underlying the overlying frame member and/ormuntin bar. In another embodiment, two peripheral edges of the central,masked region are cut so as to slightly underlie the overlying framemembers and/or muntin bars. The two, underlying edges may be adjacentedges, or opposing edges, depending on the embodiment. In yet anotherembodiment, all but one peripheral edge of the central, masked regionslightly underlies the overlying frame members and/or muntin bars.

In one example of the invention, the central, masked region underliesthe overlying frame members and/or muntin bars by about one millimeter,where the central, masked region is in fact underlying. In anotherexample, the central, masked region underlies the overlying framemembers and/or muntin bars by less than about two millimeters. Theslightly underlying, central masked regions can provide benefits incertain situations. The slightly underlying central masked regions canprovide total coverage and protection against glazing panel damage,rather than leaving a small, for example, one millimeter wideunprotected strip about the periphery of the central masked region. Thistotal protection may be appropriate in situations where subsequentprocessing of the framed glazing panel may have a deleterious affect onthe glazing panel. Having the central masked region slightly underlyinga frame member or muntin bar along only one edge may also provide a moresecure attachment of the masking material to the framed glazing panel.Allowing the central masked region to slightly underlie the framingmember and/or muntin bars can also provide for a more secure attachmentof the masking material to the framed glazing panel, where the adhesionof masking material to the glazing panel may otherwise be weak. This maybe appropriate, for example, where the adhesion of masking material toglazing panel is intentionally weak, as when the use of adhesive is notdesirable.

The slight underlying of the framing members and/or muntin bars is notbelieved to deleteriously affect the seal between the framing membersand/or muntin bars and the underlying glazing panel, as the framingmembers and/or muntin bars still have a substantial surface area fordirect contact to the underlying unmasked glazing panel. In one example,the framing member may be at least about three centimeters wide,providing more than sufficient width to allow a one or two millimeterwide inside peripheral strip of underlying masking material between theframing member and the underlying glazing panel. Thus, the greatmajority of the framing member may still directly contact the underlyingglazing panel. In another example, a muntin bar may be about ten orfifteen millimeters in width, such that a one millimeter wide strip oneither side of the muntin bar may still leave about 80% of the muntinbar to directly contact the underlying unmasked glazing panel. Allowinga slight underlying of the central masked region may thus provide manyof the advantages of the present invention, while allowing the centralmasked region to be totally removed, by pulling the underlyingperipheral regions out from under the overlying frame members and muntinbars at the time of masking material removal.

A variety of masking materials are suitable for use with the presentinvention. The masking material is preferably a polymeric film materialwhich is sufficiently clear to allow viewing the glass through themasking material. Opaque masking materials, for example, paper are alsobelieved suitable for use with the present invention. In someembodiments, polymeric film material is applied having a paper releaseliner there over, where the release liner can be removed from thecentral region of the glazing panel prior to removing the polymericmasking material.

Polyolefin films, for example, polyester or polyethylene, may be used topractice the present invention. In one method, a polyester film is used,well known to those skilled in the art. The polyester film may besupplied in a roll having an adhesive applied to one surface of themasking material and the other side of the polymeric masking materialhaving a treated surface that resists adhesion to the adhesive. In someembodiments, a release liner is provided over the adhesive to preventadhesion between the adhesive and the backside of the polymeric maskingfilm. In one embodiment, the polyester film is roll coated with anacrylic adhesive, where the polyester film has been treated with acorona or UV treatment to prevent the acrylic adhesive from adhering orsticking to the polyester film surface. The masking material should beselected such that the material absorbs the laser beam in the laserwavelength utilized. Alternatively, the laser beam wavelength isselected to be absorbed by the masking material provided.

Various lasers may be used with the present invention. In one method, a20 watt laser is utilized at approximately 4% power and a travel speedor burn speed of 9 inches per second. In another embodiment, a 10 wattlaser is used and is operated at a minimum 8% power. In yet anotherembodiment, a 20 watt laser is operated at between 4% and 15% power.When using a 10 watt laser, the power range can be between 8% and 30% offull power.

1.-18. (canceled)
 19. A glazing subassembly, comprising: a glass panelincluding a central region disposed within a peripheral region; and amasking material covering the central region and including a pluralityof closed paths formed by cuts therethrough.
 20. The subassembly ofclaim 19, wherein each of the plurality of closed paths encloses aseparate sub-region, the sub-regions space apart from one another. 21.The subassembly of claim 19, wherein each of the plurality of closedpaths form a rectangular shape.
 22. The subassembly of claim 19, whereinone of the plurality of closed paths surrounds a remainder of theplurality of closed paths.
 23. A glazing subassembly, comprising: aglass panel including a central region disposed within a peripheralregion; and a plurality of masked sub-regions disposed within thecentral region and spaced apart from one another.
 24. The subassembly ofclaim 23, further comprising a muntin bar disposed over the centralregion and extending between at least two of the plurality of maskedsub-regions.
 25. The subassembly of claim 23, wherein the sub-regionshave a rectangular shape.
 26. The subassembly of claim 23, furthercomprising a frame holding the peripheral region of the glass panel.